Allow passing raw data to Texture constructor

This facilitates being able to pass in data for use in GPGPU applications

Author: jlfwong

src/texture.js

@@ -54,7 +54,7 @@ function Texture(width, height, options) {
   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, minFilter);
   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, options.wrap || options.wrapS || gl.CLAMP_TO_EDGE);
   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, options.wrap || options.wrapT || gl.CLAMP_TO_EDGE);
-  gl.texImage2D(gl.TEXTURE_2D, 0, this.format, width, height, 0, this.format, this.type, null);
+  gl.texImage2D(gl.TEXTURE_2D, 0, this.format, width, height, 0, this.format, this.type, options.data || null);
 }
 
 var framebuffer;